Dressing die



Oct. 2, 1928.

1,686,454 F. H. LEIDECKER DRESSING DIE Filed June 12, 1925;

Patented 1928.

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Application filed June 12, 11925 Serial No. 36 741;

" This invention relates to-an' improvement in dressing dieslfor dressing spiral or straight wlnged'bits or other tools.

The object of thelnvention is provide a dressing die forshaping and sharpening the outer end or the cutting edges ofthe bit and when shaped with this die, the metal at the end of the cutting blades will be distributed so that the cutting end of the bit may be tempered evenly substantially from the center to the outer edgeof the blades. To-acconiplish this, it is essential that the transverse distance across the center ofthe bit between the water courses be'equal to the width of each of the blades at their outer edges, and that these blades gradually recede in thickness from their outer edges toward the center. V

The bit is thus tempered in the general shape of across, Where there are four blades as is the preferred form. As the cutting edges of the blades wear away, asthey do after some use, it becomes necessary to sharpen or redress these blades and to form new cutting edges thereon. The purpose of this invention is to provide a dressing die which may be used in forming these cutting edges, and, in I doing so, it will force the excess metal toward the outer surface of the blades for distributing this metal so that the blades may be evenvly tempered and set. v

In case one or more wings are shortened the excess metal not required for clearance or enlarged portion of the end ofthe bit is removed by chipping or otherwise, the die determiningthe amount of metal needed or :the amount of metal to be removed, thus acting as a gauge for each. I

The invention consists in a substantially round die having its outer end recessed properly to formthe cutting edges on the end of the bit. The die fits on or over the end of the bit and has outwardly projecting fingers which extend between the blades and are curved to the same degree as these blades, so

as to extend substantially parallel therewith.v

. The fingers are properly spaced apart sofas to leave just thedesired amount of space therebetween so as to limit the thickness of the blades and to force the excess metal 'outwardly. The slope of the recessed end of the and . In the accompanying drawings:

5 Figjlisa partial sectional.viewthrough the winged bit and die;

Fig. 2

Fig. 3 is an end view of the dressing die;

is a vertical section on line 2-2 of Fig.4 is a perspective sectional viewon line 4;4l of Fig. 1.

The numeral 1 represents the hit formed It I with a pluralityof spiralbladesQ between whlehiareprovided the water courses 3. The spiral bladesQ are formed with the substantia-lly V-shaped cuttingedges 4L at-the outer ends thereof, which cutting edges are inclined to the center 5 of the bit. There are preferably four cutting blades on each bit with the water courses 3 therebetween. These water courses are" y-shapedattheir outer end form ing a decided angle between the inner side edges of the blades,'as shown at 6.

V The die 7 is provided at its outer endwith the V-shaped recesses 8 which correspond in slope to the V-shaped cutting edges 4 on the ends of the blades. Theserecesses are also inclined toward the center to correspond to the inclination of the cutting edges 4. However, the blades and die may be straight across instead of inclined, if desired. The die'is formed with outwardly projecting fingore-9 which are V-shaped to correspond with and to fit into the V-shaped water courses3,

so j

between the blades. The fingers 9 are curved the side of the adjacent spiral Wing when ei pplied to the die. v

In dressing the bit, it isplaced or held upon an anvil and the dressing die is fitted on or The curvature in the fingers 9 prevents the same from digging into over the end thereofwith its fingers 9 proj ecting between the blades 2. The die is held and supported by means of a suspension cable carrying the same through the medium of. the eye 10, fixed to the die. The driving ram is then brought up against the end of the die or sledge hammers may be used for intermittently-applying blows tothe die for forclng it. against the bit to give the desired formation to the cutting edges of the'blades.

. In this connection, the fingers 9 prevent the metal from spreading out at the center and forces the same outwardly so as to give a,

gradual increasing thickness to the blades from the center to the outer edge thereof. This also insures that the transverse dlstance across 'the center between the water courses 3 will be maintained equal to the width of the v blades at their outer edges, so that the entire end of the bit will be evenly tempered. The metal will thus be forced iromthe center of the body and sides of the blades toward the outer edges thereof in order to form even cutting edgesot the'd-esired slope on the ends of the blades. lihis builds up the ends of the blades, as shown in Fig. l,so as to'provide a greater wearing surface while yet distributing the metalso asv to permit of the blades and center of the bit being evenly tempered. The fingers 9, being made in the general form of a spiral, corresponding to the spiral blades arenaturally given ayery slight turn each time the die is struck, by reason of the fact 7 that the sides of these lingers slide over the are no longer effective.

The bit may be dressed in the manner above described each time the cutting edges of the blades wear down to such an extent that they In this way, the blades maybe redressed over and over again until there is only a stub bit left. The evenly tempered end of the bit insures of its wean in'g off evenly instead of breaking or cracking as might be true if the die did not. force the metal outwardly from the center for permitting of its being evenly tempered.

Iclaim: P v ,7 A dressing die for cable .drill bits which have a plurality of spiral blades making less than a complete turn throughout the length of the bit, said dressing 'dieihaving spiral fingers projecting outwardly therefrom,.the twist of the fingers corresponding to the spiral twist of the spiralblades of the bit for interiitting with the blades.

In testimony whereof I aflix my signature.

FOSTER H. LEIDECKER. 

